Battery assembling apparatus and battery assembling method

ABSTRACT

Provided is a battery assembling apparatus comprising a selecting section that selects as battery cells to be assembled into a battery pack, from among a plurality of battery cells, battery cells having similar charge curves that indicate a relationship between voltage and charge period, which is a time period necessary for a battery cell to be charged from a first voltage to a second voltage that is higher than the first voltage. As a result, the lifetimes of battery cells and of a battery pack assembled from a plurality of battery cells can be extended.

The contents of the following International patent application areincorporated herein by reference: International Patent Application No.PCT/JP2010/002131 filed on Mar. 25, 2010.

BACKGROUND

1. Technical Field

The present invention relates to a battery assembling apparatus and abattery assembling method for assembling a battery pack from a pluralityof battery cells.

2. Related Art

Conventionally, a process is known that involves attaching to a batteryan IC tag, in which is recorded information concerning the type of thebattery and the like, and separating batteries with such IC tags to bereused, as described in Patent Document 1.

-   Patent Document 1: Japanese Patent Application Publication No.    2006-294382

However, battery cells that are two-dimensional batteries such aslithium ion batteries cannot be assembled into a battery pack in amanner that extends the lifetime of these battery cells.

SUMMARY

According to a first aspect related to the innovations herein, providedis a battery assembling apparatus comprising a selecting section thatselects as battery cells to be assembled into a battery pack, from amonga plurality of battery cells, battery cells having similar charge curvesthat indicate a relationship between voltage and charge period, which isa time period necessary for a battery cell to be charged from a firstvoltage to a second voltage that is higher than the first voltage.

The selecting section may select as the battery cells to be assembledinto the battery pack, from among the plurality of battery cells,battery cells having similar charge periods.

The selecting section may select as the battery cells to be assembledinto the battery pack, from among the plurality of battery cells,battery cells having similar charge periods and similar voltages at eachof a plurality of times within the charge period.

The battery assembling apparatus may further comprise a charge curvemeasuring section that charges and discharges the plurality of batterycells, and measures the charge curve of each battery cell, and theselecting section may select, as the battery cells to be assembled intothe battery pack, battery cells having similar charge curves as measuredby the charge curve measuring section.

The battery assembling apparatus may further comprise a charge curvereading section that reads information indicating the charge curves frommemories provided respectively in the plurality of battery cells, andthe selecting section may use the information indicating the chargecurves read by the charge curve reading section to select, as thebattery cells to be assembled into the battery pack, battery cellshaving similar charge curves.

The battery assembling apparatus may further comprise a purposeselecting section that selects a usage purpose for the battery pack,according to the charge curves of the battery cells selected as thebattery cells to be assembled into the battery pack.

The summary clause does not necessarily describe all necessary featuresof the embodiments of the present invention. The present invention mayalso be a sub-combination of the features described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary configuration of a battery pack 100.

FIG. 2 shows another exemplary configuration of the battery pack 100.

FIG. 3 shows an exemplary power supplying system 200.

FIG. 4 shows an exemplary configuration of a power supplying apparatus210.

FIG. 5 shows an exemplary configuration of a vehicle 220.

FIG. 6 shows an exemplary driving environment table 214.

FIG. 7 shows an overview of repacking battery cells.

FIG. 8 shows an exemplary configuration of a battery assemblingapparatus 310.

FIG. 9 shows exemplary charge curves of three battery cells 301 havingdifferent charge curves.

FIG. 10 shows other exemplary charge curves of three battery cells 301having different charge curves.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, some embodiments of the present invention will bedescribed. The embodiments do not limit the invention according to theclaims, and all the combinations of the features described in theembodiments are not necessarily essential to means provided by aspectsof the invention.

FIG. 1 shows an exemplary configuration of a battery pack 100. Thebattery pack 100 includes a plurality of batteries 102 and a pluralityof memories 106 that correspond respectively to the batteries 102 andthat each record deterioration information of the corresponding battery102. Each battery 102 may be formed integrally with the correspondingmemory 106 to create a battery cell 101. Each battery 102 is formed of apair of electrodes. The battery 102 in each battery cell 101 is formedof a pair of electrodes, each battery cell 101 includes an exteriorportion that shields the pair of electrodes from the outside, and eachmemory 106 is provided within a corresponding exterior portion. Eachbattery 102 may be a two-dimensional battery, such as a lithium-ionbattery.

Each memory 106 records the deterioration information of thecorresponding battery 102. Each battery cell 101 of the battery pack 100is detachably connected to another battery cell 101, and the batterypack 100 can be disassembled to remove each battery cell 101 withoutdamaging the battery cells 101. For example, the battery cells 101 maybe connected by screws, bolts, nuts, or the like. Instead, the batterycells 101 can be connected to each other in a fixed state by exertingpressure on the battery cells 101 without using bolts or nuts. Forexample, the battery cells 101 may be pressed against each other andconnected by a retractable substance such as rubber. As another example,the battery cells 101 may be connected by being pressed by an exteriorportion of the battery pack 100.

Each battery cell 101 may include a voltage detecting section 103 thatdetects voltage of the corresponding battery 102. Each battery cell 101may include a current detecting section 104 that detects current of thecorresponding battery 102. The voltage detecting sections 103 and thecurrent detecting sections 104 are disposed within the exterior portionsof the battery cells 101. In the present Specification, the voltagedetecting sections 103 and the current detecting sections 104 can bereferred to generally as “detecting sections.” Each memory 106 recordsdeterioration information of the corresponding battery 102 based on atleast one of the voltage of the battery 102 and current of the battery102 detected by the detecting sections of the corresponding battery cell101.

Each battery cell 101 may include a deterioration informationcalculating section 105 that calculates the deterioration information ofthe corresponding battery 102 based on the information concerning atleast one of the voltage and the current detected by the correspondingdetecting sections. Each memory 106 records the deteriorationinformation calculated by the corresponding deterioration informationcalculating section 105. Here, the deterioration information calculatingsection 105 “corresponding” to a memory 106 refers to the deteriorationinformation calculating section 105 disposed in the same battery cell101 as the memory 106. Each deterioration information calculatingsection 105 may be realized by an information processing device such asa CPU. In this case, each information processing device may include arecording medium in which a prescribed program is recorded, and mayfunction as a deterioration information calculating section 105according to this prescribed program. As another example, eachdeterioration information calculating section 105 may be realized by anelectric circuit or an electronic circuit. Each deteriorationinformation calculating section 105 includes a clock circuit thatmeasures time. For ease of explanation, the following description dealswith one battery cell 101, but each battery cell 101 may have the sameconfiguration.

The memory 106 may record, as the deterioration information, at leastone of the number of times the battery 102 is charged and discharged,the history of the voltage of the battery 102, the history of thecurrent of the battery 102, the voltage of the battery 102 when chargingis begun, the voltage of the battery 102 when charging is finished, theinternal resistance value of the battery 102 and change thereof, acharge curve of the battery 102, and a deterioration curve of thebattery 102. The number of times the battery 102 is charged anddischarged is measured such that a cycle of charging and discharging iscounted as 1 time. In other words, the period from when the battery 102is charged to the next charging of the battery 102 may be counted as 1time. The charge/discharge count can be measured according to thevoltage history and the current history. The deterioration informationcalculating section 105 may calculate the number of charge/dischargetimes based on the voltage history, or based on the current history.

The voltage history indicates the change in the voltage of the battery102 over time. In other words, the voltage history can be obtained byrecording the voltage detected by the voltage detecting section 103 overeach of a plurality of predetermined periods. When recording the voltagehistory in the memory 106 as the deterioration information, thedeterioration information calculating section 105 may record a valueindicating the voltage detected by the voltage detecting section 103over each predetermined period in the memory 106 as-is. The currenthistory indicates the change in the current of the battery 102 overtime. In other words, the current history can be obtained by recordingthe current detected by the current detecting section 104 over each of aplurality of predetermined periods. When recording the current historyin the memory 106 as the deterioration information, the deteriorationinformation calculating section 105 may record a value indicating thecurrent detected by the current detecting section 104 over eachpredetermined period in the memory 106 as-is.

The voltage of the battery 102 when charging is begun can be referred tohereinafter as “charge-start voltage.” When recording the charge-startvoltage in the memory 106 as the deterioration information, thedeterioration information calculating section 105 records a value of thevoltage detected by the voltage detecting section 103 when chargingbegins in the memory 106 as-is. The voltage of the battery 102 whencharging is finished can be referred to hereinafter as “charge-endvoltage.” When recording the charge-end voltage in the memory 106 as thedeterioration information, the deterioration information calculatingsection 105 records a value of the voltage detected by the voltagedetecting section 103 when the battery 102 is fully charged or whencharging ends in the memory 106 as-is.

The internal resistance value of the battery 102 can be calculated basedon the current and the voltage of the battery 102. When storing theinternal resistance value in the memory 106 as the deteriorationinformation, the deterioration information calculating section 105 maycalculate the internal resistance value based on the voltage detected bythe voltage detecting section 103 and the current detected by thecurrent detecting section 104, and record the result in the memory 106.Change in the internal resistance value can be obtained by calculatingthe internal resistance value in each of a plurality of predeterminedperiods and storing the results. The charge curve indicates arelationship between the voltage and the charge period during chargingof the battery 102. When recording the charge curve as the deteriorationinformation, the deterioration information calculating section 105 maycalculate the charge curve based on a value indicating the voltagedetected by the voltage detecting section 103 from when charging isbegun to when charging is finished, and may record the result in thememory 106. As another example, the deterioration informationcalculating section 105 may store a value indicating the voltagedetected from when charging is begun to when charging is finished in thememory 106 as-is.

The deterioration curve indicates the deterioration history of thebattery 102. The deterioration curve may indicate the change of thevoltage of the battery 102 when fully charged. The deterioration curvemay indicate a relationship between the number of times the battery 102is charged and the voltage of the battery 102 when fully charged. As thenumber of times the battery 102 is charged increases, the voltage of thebattery 102 when fully charged decreases. In other words, as thedeterioration progresses, the voltage of the battery 102 when fullycharged decreases. When storing the deterioration curve as thedeterioration information, the deterioration information calculatingsection 105 may record the present number of times the battery 102 hasbeen charged and the voltage of the battery 102 when fully charged inthe memory 106. The deterioration information calculating section 105may calculate the deterioration curve based on the informationconcerning the voltage of the battery 102 and the number of times thebattery 102 was charged recorded in the memory 106, and record theresulting deterioration curve in the memory 106. The deteriorationinformation calculating section 105 may calculate the deteriorationcurve based on the deterioration curve stored in the memory 106 and thefully-charged voltage of the battery 102 detected after a new charging,and store the resulting deterioration curve. The deterioration curve mayindicate change in the internal resistance of the battery 102. As theinternal resistance value of the battery 102 increases, deterioration ofthe battery 102 progresses. The deterioration curve may indicate arelationship between the internal resistance of the battery 102 and thenumber of times the battery 102 is charged. As the number of times thebattery 102 is charged increases, the internal resistance of the battery102 also increases.

The memory 106 may record temperature of the battery 102 as thedeterioration information. The deterioration of the battery 102 changesaccording to the temperature of the battery 102. In this case, thebattery pack 100 includes therein a temperature sensor that detects thetemperatures of the batteries 102. A temperature sensor may be providedwithin the exterior portion of each battery cell 101. Each temperaturesensor detects the temperature of the corresponding battery 102. Here,the battery 102 “corresponding” to a temperature sensor is the battery102 within the same battery cell 101 as the temperature sensor. Asanother example, a temperature sensor may be provided inside the batterypack 100 but outside of the battery cells 101.

Each battery cell 101 may include an output interface 107 for outputtingthe deterioration information from the memory 106 to the outside of thebattery cell 101. In this way, the deterioration information stored inthe memory 106 of each battery cell 101 can be read from an externalapparatus.

The battery pack 100 of the present embodiment includes a plurality ofgroups that each include a plurality of battery cells 101 arrangedserially, and these groups are arranged in parallel. However, this ismerely one example, and the battery pack 100 may include battery cells101 that are all connected serially or battery cells 101 that are allconnected in parallel. If battery cells 101 are connected serially, thecurrent flowing through each serially connected battery cell 101 is thesame. Therefore, only one current detecting section 104 is required foreach set of battery cells 101 connected serially. In this case, thecurrent detecting section 104 may be provided outside the battery cells101. As another example, the current detecting section 104 may beprovided to one of the battery cells 101 connected serially and not tothe other battery cells 101 in the same serial connection. In this case,the current detecting section 104 provided to one of the battery cells101 may detect the current of the batteries 102 in the battery cells 101not provided with a current detecting section 104.

Furthermore, a voltage detecting section 103 may be provided in one ofthe battery cells 101 and not in the other battery cells 101 in the sameserial connection. In this case, the voltage detecting section 103provided in one of the battery cells 101 may detect the voltage of thebatteries 102 in the battery cells 101 not provided with a voltagedetecting section 103. A deterioration information calculating section105 may be provided in one of the battery cells 101 and not in the otherbattery cells 101 in the same serial connection. In this case, thedeterioration information calculating section 105 provided in one of thebattery cells 101 may calculate the deterioration information for eachof the batteries 102 in the battery cells 101 not provided with adeterioration information calculating section 105. In the abovedescription, the voltage detecting sections 103, current detectingsections 104, and deterioration information calculating sections 105 areprovided within the battery cells 101, but only the memories 106 must beprovided in the battery cells 101, and at least one of the voltagedetecting sections 103, the current detecting sections 104, and thedeterioration information calculating sections 105 may be providedoutside the battery cells 101.

FIG. 2 shows another exemplary configuration of the battery pack 100.Components that are the same as those in FIG. 1 are given the samereference numerals. The battery pack 100 includes a plurality ofbatteries 102 and a plurality of memories 106 that correspondrespectively to the batteries 102 and record the deteriorationinformation of the corresponding batteries 102. Each battery 102 isformed integrally with the corresponding memory 106 to create a batterycell 111. Each battery 102 is formed of a pair of electrodes. Eachbattery cell 111 includes a battery 102 formed of a pair of electrodesand an exterior portion that shields the pair of electrodes from theoutside, and each memory 106 is provided within a corresponding exteriorportion. Each memory 106 records the deterioration information of thecorresponding battery 102. Each battery cell 111 of the battery pack 100is detachably connected to another battery cell 111, and the batterypack 100 can be disassembled to remove each battery cell 111 withoutdamaging the battery cells 111.

The battery pack 100 may include a voltage detecting section 112 thatdetects the voltage of each of the batteries 102. The voltage detectingsection 112 is provided within the battery pack 100 and outside of thebattery cells 111. The battery pack 100 may include a plurality ofvoltage detecting sections 112. The battery pack 100 may include acurrent detecting section 113 that detects the current of each of thebatteries 102. The current detecting section 113 is provided within thebattery pack 100 and outside of the battery cells 111. The battery pack100 may include a plurality of current detecting sections 113. In thepresent Specification, the voltage detecting sections 112 and currentdetecting sections 113 can be referred to generally as “detectingsections.” Each memory 106 records the deterioration information of thecorresponding battery 102 based on at least one of the voltage and thecurrent of the battery 102 detected by the detecting sections.

Each memory 106 may record, as the deterioration information, at leastone of the number of times the battery 102 is charged and discharged,the history of the voltage of the battery 102, the history of thecurrent of the battery 102, the voltage of the battery 102 when chargingis begun, the voltage of the battery 102 when charging is finished, theinternal resistance value of the battery 102 and change thereof, acharge curve of the battery 102, and a deterioration curve of thebattery 102. Each memory 106 may store the temperature of the battery102 as the deterioration information. In this case, the battery pack 100includes therein a temperature sensor that detects the temperatures ofthe batteries 102. The temperature sensor may be provided within thebattery pack 100 and outside the battery cells 111. As another example,the battery pack 100 may include a plurality of temperature sensorscorresponding respectively to the batteries 102. In this case, eachtemperature sensor may be provided within the exterior portion of thecorresponding battery cell 111.

The battery pack 100 may include a deterioration information calculatingsection 114 that calculates the deterioration information of eachbattery 102 based on information concerning at least one of the detectedvoltage and current of the battery 102. The deterioration informationcalculating section 114 is provided within the battery pack 100 andoutside of the battery cells 111. The deterioration informationcalculating section 114 may be realized by an information processingdevice such as a CPU or by an electrical circuit or electronic circuit,in the same manner as the deterioration information calculating section105. Each memory 106 records the deterioration information of thecorresponding battery 102. The deterioration information calculatingsection 114 includes a clock circuit that measures time.

Each battery cell 111 may include an input/output interface 115 forreceiving deterioration information being written to the memory 106 fromoutside the battery cell 111 and outputting the deteriorationinformation from the memory 106 to the outside of the battery cell 111.As another example, each battery cell 111 may include an input interfacefor receiving deterioration information being written to the memory 106from outside the battery cell 111 and a separate output interface foroutputting the deterioration information from the memory 106 to theoutside of the battery cell 111.

The deterioration information calculating section 114 records thedeterioration information of the batteries 102 to the memories 106 viathe input/output interfaces 115 of the battery cells 111. Thedeterioration information calculating section 114 records thedeterioration information of each battery 102 to the memory 106corresponding to the battery 102.

The voltage detecting section 112, the current detecting section 113,and the deterioration information calculating section 114 are describedas being outside the battery cells 111, but instead, at least one of thevoltage detecting section 112, the current detecting section 113, andthe deterioration information calculating section 114 may be providedwithin one of the battery cells 111.

As described above, each memory 106 provided to a battery cell 101records the deterioration information of the corresponding battery 102,and therefore even when the battery pack 100 is disassembled and thebattery cells 101 are mixed up, it is easy to find the deteriorationinformation for the battery 102 of each battery cell 101. In otherwords, even when the battery pack 100 is disassembled into individualbattery cells 101, it is easy to find the deterioration information forthe battery 102 of each battery cell 101.

The battery pack 100 described above can be used as a battery mounted ina vehicle. This vehicle battery may be formed of one or more batterypacks 100. The following describes a power supplying system thatincludes a vehicle in which the vehicle battery is mounted and a powersupplying apparatus that supplies power to the vehicle.

FIG. 3 shows an exemplary power supplying system 200. The powersupplying system 200 includes a power supplying apparatus 210, a vehicle220, and a cable 230. The vehicle 220 includes a vehicle battery 221 andequipment 222. The vehicle 220 may be an electric vehicle or a hybridvehicle. The vehicle 220 may be any type of vehicle in which a vehiclebattery 221 is mounted. The cable 230 connects the power supplyingapparatus 210 to the vehicle 220. The cable 230 conducts the powersupplied by the power supplying apparatus 210 to the vehicle 220. Thecable 230 may include a dedicated power line and a dedicatedcommunication line. The dedicated power line conducts the power suppliedfrom the power supplying apparatus 210 to the vehicle 220. The dedicatedcommunication line transmits a control signal from the power supplyingapparatus 210 to the vehicle 220. The equipment 222 adjusts the drivingenvironment of the vehicle 220. The equipment 222 may be an airconditioner that adjusts the temperature in the vehicle 220, forexample. The air conditioner adjusts the temperature within the vehicle220 by performing at least one of heating and cooling. The equipment 222may be a defogger that heats defogger wires provided in glass to removemist from the glass. The equipment 222 may be a seat warmer that warmsthe seats of the driver or passengers.

The power supplying apparatus 210 may be provided in a building 240,such as a house or apartment. The power supplying apparatus 210 maysupply the vehicle 220 with power from a power company via the cable230. The power supplying apparatus 210 may include fuel batteries, solarbatteries, or electric generators, and may supply the vehicle 220 withthe power generated by these fuel batteries, solar batteries, orelectric generators. The power supplying apparatus 210 may include arechargeable battery and supply the vehicle 220 with power accumulatedin the rechargeable battery. The power supplying apparatus 210 suppliespower for charging the vehicle battery 221 of the vehicle 220. The powersupplying apparatus 210 supplies the power to the vehicle 220 via thededicated output line of the cable 230.

The power supplying apparatus 210 controls the equipment 222 of thevehicle 220 by transmitting a control signal via the cable 230. Thepower supplying apparatus 210 may control the equipment 222 according toat least one of the internal temperature and the external temperature ofthe vehicle 220. The power supplying apparatus 210 may control theequipment 222 based on information registered by a user for controllingthe equipment 222. The power supplying apparatus 210 may control theequipment 222 based on a driving environment registered by the user. Forexample, the power supplying apparatus 210 may control the equipment 222such that the internal temperature of the vehicle 220 is a temperatureregistered by the user. As another example, the power supplyingapparatus 210 may control the equipment 222 such that the internaltemperature of the vehicle 220 becomes a temperature registered by theuser at a time registered by the user. The power supplying apparatus 210may generate the control signal for controlling the equipment 222. Thepower supplying apparatus 210 may control the equipment 222 bytransmitting the control signal thereto via the dedicated communicationline of the cable 230. The cable 230 need not include the designatedcommunication line. In this case, the power supplying apparatus 210 maycontrol the equipment 222 by transmitting the control signal thereto viathe cable 230 using power communication.

FIG. 4 shows an exemplary configuration of the power supplying apparatus210. The power supplying apparatus 210 includes an external temperaturedetecting section 211, a temperature acquiring section 212, a drivingenvironment registering section 213, a driving environment table 214, avehicle control section 215, a power supplying section 216, and acontrol section 217.

The external temperature detecting section 211 detects externaltemperature. The external temperature detecting section 211 may includea temperature sensor. The temperature acquiring section 212 acquires theexternal temperature detected by the external temperature detectingsection 211. The temperature acquiring section 212 may acquire thetemperature detected by a temperature detecting section provided to thevehicle 220. The temperature acquiring section 212 may acquire at leastone of the detected external temperature and internal temperature of thevehicle 220.

The driving environment registering section 213 receives the drivingenvironment input by the user. The driving environment registeringsection 213 registers the driving environment by recording informationinput by the user indicating the driving environment in the drivingenvironment table 214. The vehicle control section 215 acquires thedriving environment information input by the user from the drivingenvironment table 214. The vehicle control section 215 may control theequipment 222 according to the acquired external temperature. When thetemperature acquiring section 212 acquires the internal temperature ofthe vehicle 220, the vehicle control section 215 may control theequipment 222 according to the acquired internal temperature. Thevehicle control section 215 may control the equipment 222 according toboth the internal temperature and the external temperature. The vehiclecontrol section 215 may control the equipment 222 according to thedriving environment input by the user. The vehicle control section 215may control the equipment 222 according to the driving environment andto the external temperature and/or the internal temperature. The vehiclecontrol section 215 may generate a control signal for controlling theequipment 222. The vehicle control section 215 may control the equipment222 by transmitting the control signal to the vehicle 220 via the cable230.

The power supplying section 216 supplies the vehicle 220 with power froma power company via the cable 230. The power supplying section 216supplies the vehicle 220 with the power via the dedicated power line ofthe cable 230. The power supplying section 216 converts the alternatingcurrent of the power company into direct current, and supplies thedirect current power to the vehicle 220. The control section 217controls each component of the power supplying apparatus 210. When aconnection between the vehicle 220 and the power supplying apparatus 210is detected, the control section 217 may control the equipment 222 usingthe vehicle control section 215 and supply power to the vehicle 220using the power supplying section 216. The control section 217 may judgethe vehicle 220 to be connected to the power supplying apparatus 210when a signal is received from the vehicle 220. For example, the controlsection 217 may judge this connection to be established when acommunication signal is sent from the control section 217 to the vehicle220 and a response signal is sent back to the control section 217 fromthe vehicle 220 in response to the communication signal. The temperatureacquiring section 212, the driving environment registering section 213,the driving environment table 214, the vehicle control section 215, andthe control section 217 may be realized as an information processingdevice such as a CPU. The power supplying apparatus 210 may include arecording medium on which is recorded a prescribed program, and theinformation processing device may function as the power supplyingapparatus 210 according to the prescribed program.

FIG. 5 shows an exemplary configuration of the vehicle 220. The vehicle220 includes the vehicle battery 221, the equipment 222, a powerswitching section 223, and an equipment control section 224. The vehiclebattery 221 accumulates power for moving an electrical system such asthe equipment 222 or a motor of the vehicle 220. The vehicle battery 221may be a lithium ion battery, or another type of two-dimensionalbattery. The equipment 222 includes at least one of an air conditioner,a defogger, and a seat warmer.

The power switching section 223 switches the destination of the powersupplied from the power supplying section 216 via the cable 230 to bethe vehicle battery 221 or the equipment 222. The power switchingsection 223 supplies the power to the vehicle battery 221 until thevehicle battery 221 is fully charged. In this case, the vehicle battery221 supplies the equipment 222 with the power accumulated therein. Thepower switching section 223 supplies the equipment 222 with power whenthe vehicle battery 221 is fully charged. In this case, the poweraccumulated in the vehicle battery 221 is not supplied to the equipment222. A determination concerning whether the vehicle battery 221 is fullycharged can be made based on the voltage of the vehicle battery 221, forexample. The power switching section 223 may supply the vehicle battery221 and the equipment 222 in parallel with the power transmitted via thecable 230. In other words, the power switching section 223 may supplythe power simultaneously to the vehicle battery 221 and the equipment222. The power switching section 223 may include a switch and aninformation processing device, and may switch the destination of thesupplied power by controlling the switch with the information processingdevice.

The equipment control section 224 controls the equipment 222 accordingto the control signal transmitted from the vehicle control section 215via the cable 230. The equipment control section 224 may control theequipment 222 by transmitting the control signal from the vehiclecontrol section 215 to the equipment 222 as-is. As another example, theequipment control section 224 may control the equipment 222 bygenerating, according the control signal transmitted from the vehiclecontrol section 215, a control signal for controlling the equipment 222.The equipment control section 224 may be realized by an informationprocessing device. The vehicle 220 may include a recording medium onwhich is recorded a prescribed program, and the information processingdevice may be caused to function as the equipment control section 224according to the prescribed program.

FIG. 6 shows an exemplary driving environment table 214. The time thatthe user uses the vehicle 220, the type of equipment 222 beingcontrolled, and the driving environment are recorded in the drivingenvironment table 214. IN the driving environment table 214, the usagetime is recorded as “2009/2/20, 7:30,” “2009/2/20, 20:00,” and“2009/2/21, 13:00,” for example. The content recorded for the type ofequipment 222 being controlled includes the “air conditioner,” the“defogger,” and the “seat warmer,” and adjustments according to eachtype of equipment 222 are recorded as the content for the drivingenvironment. For example, for the vehicle 220 usage time of Feb. 20,2009, at 7:30, the driving environments for the recorded types ofequipment 222 respectively indicate that the air conditioner maintainsan internal temperature of 25 degrees, the defogger is turned on, andthe seat warmer is set to a high temperature. For the vehicle 220 usagetime of Feb. 21, 2009, at 13:00, the driving environments for therecorded types of equipment 222 respectively indicate that the airconditioner maintains an internal temperature of 26 degrees, thedefogger is turned off, and the seat warmer is turned off In this way,the user can input vehicle 220 usage times and driving environments forthese times, and the driving environment registering section 213 canregister the information input by the user by recording this informationin the driving environment table 214.

The following describes the operation of the power supplying system 200.When the control section 217 of the power supplying apparatus 210detects that the power supplying apparatus 210 and the vehicle 220 areconnected via the cable 230, the control section 217 causes the powersupplying section 216 to supply power to the vehicle 220. The controlsection 217 need not control the power supplying section 216. In thiscase, the power supplying section 216 may automatically supply power tothe vehicle 220 when the vehicle 220 is connected to the power supplyingapparatus 210 via the cable 230. For example, the power supplyingsection 216 may be in a state of constantly supplying power, therebyacting in the same manner as a home electrical outlet that suppliespower whenever a plug is inserted therein. The power switching section223 of the vehicle 220 supplies the vehicle battery 221 with the powertransmitted from the power supplying section 216. As a result, thevehicle battery 221 can be charged. At this time, when the equipment 222requires power, the vehicle battery 221 may supply the needed power tothe equipment 222. When the vehicle battery 221 is fully charged, thepower switching section 223 switches the destination of the suppliedpower from the vehicle battery 221 to the equipment 222. Furthermore,when the vehicle battery 221 is fully charged and the equipment 222 doesnot require power, the power switching section 223 provides power toneither the vehicle battery 221 nor the equipment 222. Instead ofsupplying power to only one of the vehicle battery 221 and the equipment222 at a time, the power switching section 223 may supply power to boththe vehicle battery 221 and the equipment 222 in parallel.

When the control section 217 detects that the power supplying apparatus210 and the vehicle 220 are connected via the cable 230, the controlsection 217 causes the vehicle control section 215 to control theequipment 222 of the vehicle 220. The vehicle control section 215acquires the external temperature acquired by the temperature acquiringsection 212. The temperature acquiring section 212 may acquire theexternal temperature detected by the external temperature detectingsection 211. Instead, the temperature acquiring section 212 may acquirethe external temperature from the vehicle 220. In this case, the vehicle220 may include a temperature sensor that detects the externaltemperature. The vehicle control section 215 acquires from the drivingenvironment table 214 information indicating the next vehicle 220 usagetime and the driving environment corresponding to this usage time. Thevehicle control section 215 generates the control signal for controllingthe equipment 222, based on the information indicating the acquiredexternal temperature, the usage time, and the driving environment.

More specifically, the vehicle control section 215 estimates the currentinternal temperature of the vehicle 220 based on the acquired externaltemperature. The vehicle control section 215 may include a table inwhich external temperature is associated with internal temperature, andmay estimate the internal temperature based on this table. At a givenusage time, the vehicle control section 215 controls the equipment 222to create the driving environment corresponding to this usage time.Here, the vehicle control section 215 controls the equipment 222according to the estimated internal temperature. For example, as shownin FIG. 6, when the acquired usage time is “2009/2/20 20:00,” theregistered internal temperature is “27 degrees,” and so the vehiclecontrol section 215 generates a control signal that causes the airconditioner to set the internal temperature of the vehicle 220 to 27degrees at 8:00 p.m. on Feb. 20, 2009, and transmits this control signalto the vehicle 220. As a result, the internal temperature of the vehicle220 can be set to the registered temperature at the corresponding usagetime. The vehicle control section 215 may change the control signal forcontrolling the air conditioner, according to the difference between thecurrent internal temperature and the registered internal temperature.The content of the control signal may include the start time of the airconditioning or the strength of the air conditioning by the airconditioner. When there is a long interval between the air conditioningstart time and the usage time, the strength of the air conditioning maybe lower than when this interval is shorter. When the difference betweenthe current internal temperature and the registered internal temperatureis smaller, the strength of the air conditioning may be lower than whenthis difference is larger. The strength of the air conditioning affectsthe speed at which the current temperature reaches the registeredtemperature. When the strength of the air conditioning is high, the timenecessary for the current internal temperature to change to theregistered internal temperature is shorter than when this strength islow.

When the acquired usage time is “2009/2/20 20:00,” the defogger isturned “on,” and therefore the vehicle control section 215 generates acontrol signal that causes the defogger to begin heating the defoggerwires at a time that is a predetermined time earlier than the usage timeof 8:00 p.m. on Feb. 20, 2009, and provides this control signal to thevehicle 220. As a result, mist can be removed from the glass of thevehicle 220 at the corresponding usage time. When the acquired usagetime is “2009/2/20 20:00,” the seat warmer is set to “medium,” andtherefore the vehicle control section 215 generates a control signalthat causes the seat warmer to warm the seats with “medium” strength ata time that is a predetermined time earlier than the usage time, andsupplies this control signal to the vehicle 220. The strength of theseat warmer indicates the temperature to which the seats are warmed. Asa result, the seats of the vehicle 220 can be warmed at thecorresponding usage time. In this way, the driving environment of thevehicle 220 can be adjusted from a remote location, such as inside abuilding, without the user needing to go out to the vehicle 220.

When the temperature acquiring section 212 acquires the internaltemperature from the vehicle 220, the vehicle control section 215generates a control signal for controlling the equipment 222 based onthe current internal temperature, the usage time, and the drivingenvironment corresponding to the usage time. In this case, it is notnecessary to estimate the internal temperature of the vehicle 220.Furthermore, since the internal temperature of the vehicle 220 isdetected, the vehicle control section 215 can judge whether the detectedinternal temperature is equal to the registered internal temperature andcan accurately control the internal temperature of the vehicle 220.

The equipment control section 224 of the vehicle 220 controls theequipment 222 according to the control signal transmitted from thevehicle control section 215. The equipment control section 224 maycontrol the equipment 222 by transmitting the control signal receivedfrom the vehicle control section 215 to the equipment 222 as-is.

Since the equipment 222 of the vehicle 220 is controlled from the powersupplying apparatus 210 in the manner described above, the vehicle 220can be controlled without the user needing to go to the vehicle 220.Furthermore, the equipment 222 is controlled according to the externaltemperature, and therefore the driving environment of the vehicle 220can be adjusted to match the driving environment corresponding to theexternal temperature. In addition, as a result of the user registeringdriving environments, the driving environment of the vehicle 220 can beadjusted by the user as desired. Since the vehicle battery 221 is beingcharged, the driving environment can be adjusted without the driving ofthe equipment 222 decreasing the power of the vehicle battery 221. Theequipment 222 is driven by the power from the power company when thevehicle battery 221 is fully charged, and therefore the drivingenvironment can be adjusted without decreasing the power of the vehiclebattery 221. Furthermore, lack of power for the vehicle battery 221 dueto adjustment of the driving environment, which could prevent thevehicle 220 from being driven, is prevented.

The vehicle control section 215 may control the equipment 222 accordingto only the temperature acquired by the temperature acquiring section212, without acquiring a driving environment from the drivingenvironment table 214. In this case, the vehicle control section 215 maycontrol the equipment 222 to create a predetermined driving environment.For example, when the external temperature is lower than a firsttemperature, the air conditioner may be powered to perform heating andthe defogger and seat warmer may be turned on. When the externaltemperature is higher than a second temperature, the air conditioner maybe powered to perform cooling and the defogger and seat warmer may beturned off. The first temperature may be less than or equal to thesecond temperature. The vehicle control section 215 may control theequipment 222 according to only the driving environment acquired fromthe driving environment table 214, without consideration to thetemperature acquired by the temperature acquiring section 212. Thevehicle control section 215 may control the equipment 222 bytransmitting to the equipment control section 224 information indicatingthe driving environment acquired from the driving environment table 214.In this case, the vehicle control section 215 controls the equipment 222according to the driving environment acquired by the equipment controlsection 224.

If the power supplying apparatus 210 is provided outside of the building240, an information processing device such as a computer may be providedin the building 240 and connected to the power supplying apparatus 210.In this case, the information processing device provided in the buildingmay be used to register the driving environment input by the user. Inother words, the information processing device may function as thedriving environment registering section 213 and the driving environmenttable 214. Furthermore, the information processing device provided inthe building 240 may generate the control signal for controlling theequipment 222 and transmit the control signal to the power supplyingapparatus 210. In this case, the vehicle control section 215 of thepower supplying apparatus 210 controls the equipment 222 by transmittingthe control signal received from the information processing device tothe vehicle 220 via the cable 230.

In the above description, the power supplying apparatus 210 is connectedto the vehicle 220 via the cable 230 and the power supplying apparatus210 supplies power and transmits the control signal to the vehicle 220via the cable 230. Instead, the power supplying apparatus 210 may supplypower and transmit the control signal to the vehicle 220 without usingthe cable 230. For example, the power supplying apparatus 210 may supplythe vehicle 220 with power using microwave power transmission. The powersupplying apparatus 210 may transmit the control signal to the vehicle220 using microwave communication.

The battery pack used as the vehicle battery 221 if the vehicle 220 inthe above description can be recycled and disassembled into individualbattery cells. The battery cells can then be repacked and used again.The following describes a battery assembling apparatus used forrepacking battery cells.

FIG. 7 shows an overview of repacking battery cells. Here, a pluralityof used battery packs 300 are each disassembled into individual batterycells 301. In other words, the battery packs 300 are disassembled andthe battery cells 301 are mixed up. A group of battery cells 301 havingsimilar charge curves are selected from among the randomly mixed batterycells 301 to be assembled into one battery pack. The group of selectedbattery cells 301 is assembled as a single battery pack to form abattery pack 300. The battery cells 301 may be the same as the batterycells 101 shown in FIG. 1 or the battery cells 111 shown in FIG. 2. Thebattery cell 301 need not include memories 106.

FIG. 8 shows an exemplary configuration of a battery assemblingapparatus 310. The battery assembling apparatus 310 includes a chargecurve acquiring section 311, a selecting section 312, and a purposeselecting section 313. The charge curve acquiring section 311 acquiresthe charge curve of each of a plurality of battery cells 301. The chargecurve acquiring section 311 includes a charge curve measuring section321 and a charge curve reading section 322. An information processingdevice may function as the battery assembling apparatus 310 by reading aprescribed program. The information processing device may include arecording medium on which the prescribed program is recorded.

The charge curve measuring section 321 charges and discharges thebattery cells 301, and measures the charge curve of each battery cell301. In this way, the charge curve of each battery cell 301 can beobtained. Each charge curve indicates a relationship between the voltageand the charge period, which is the time necessary for the battery cell301 to be charged from a first voltage to a second voltage that ishigher than the first voltage. The charge curve measuring section 321discharges each battery cell 301 to the first voltage, and then chargesthe battery cell 301. The charge curve measuring section 321 can measureeach charge curve by measuring the charge period necessary for thevoltage of the corresponding battery cell 301 to change from the firstvoltage to the second voltage and measuring the voltage at each point intime during the charge period. The charge curve measuring section 321includes a control section that controls the charging and discharging ofthe battery cells 301. The control section may be realized by aninformation processing device. The charge curve measuring section 321may supply the battery cells 301 with power from the power company. Thecharge curve measuring section 321 may supply the battery cells 301 withpower generated by fuel batteries, solar batteries, or electricgenerators provided thereto. The second voltage may be the voltagereached when a battery cell 301 is fully charged.

The charge curve reading section 322 reads information indicating thecharge curve of each battery cell 301, from the memories providedrespectively to the battery cells 301. If the battery cells 301 are thesame as the battery cells 101 shown in FIG. 1, the charge curve readingsection 322 reads the information indicating the charge curves recordedin the memories 106 via the output interfaces 107. If the battery cells301 are the same as the battery cells 111 shown in FIG. 2, the chargecurve reading section 322 reads the information indicating the chargecurves recorded in the memories 106 via the input/output interfaces 115.The information indicating each charge curve may be informationdisplaying the charge curve itself, or may be information allowing thecharge curve to be understood. For example, each charge curve may be thevoltage history of the corresponding battery cell 301. In his case, thecharge curve reading section 322 may read the voltage history of abattery cell 301 from the corresponding memory 106 and calculate thecorresponding charge curve based on this voltage history. Theinformation indicating each charge curve may be information indicatingthe voltage history and the change of the internal resistance value ofthe corresponding battery 102. In this case, the charge curve readingsection 322 may read the voltage history and the change of the internalresistance value from the corresponding memory 106 and calculate thecharge curve based on this voltage history and change of the internalresistance value. The charge curve reading section 322 may be realizedby an information processing device such as a CPU, or by an electricalcircuit or an electronic circuit.

For a battery cell 301 that does not include a memory in whichinformation indicating the charge curve is recorded, the charge curvethereof is preferably measured by the charge curve measuring section321. For a battery cell 301 that does include a memory in whichinformation indicating the charge curve is recorded, the charge curvethereof is preferably read by the charge curve reading section 322. Evenfor a battery cell 301 that does not include a memory, if there is arecording medium in which is recorded information indicating the chargecurve of this battery cell 301, the charge curve reading section 322 mayread the information indicating the charge curve from the recordingmedium. The charge curve acquiring section 311 may judge whether eachbattery cell 301 includes a memory 106 in which is recorded informationindicating the charge curve, and determine whether the charge curvemeasuring section 321 or the charge curve reading section 322 acquiresthe charge curve based on this judgment.

The selecting section 312 selects, as the battery cells to be assembledinto one battery pack, battery cells 301 having similar charge curvesacquired by the charge curve acquiring section 311 from among theplurality of battery cells 301. If the number of battery cells 301having similar charge curves is less than the number of battery cells tobe assembled as a battery pack, the selecting section 312 need notselect battery cells to be assembled as a battery pack. If the number ofbattery cells 301 having similar charge curves is greater than thenumber of battery cells to be assembled as a battery pack, the selectingsection 312 may select only the number of battery cells needed toassemble the one battery pack.

Battery cells 301 having similar charge curves refer to battery cells301 for which the path of the charge curve is within a predeterminedrange. The selecting section 312 may judge battery cells 301 havingsimilar charge periods as being the battery cells 301 having similarcharge curves. The selecting section 312 may then select, as the batterycells to be assembled as one battery pack, the battery cells 301 judgedto have similar charge curves. Battery cells 301 having similar chargeperiods may refer to battery cells 301 with matching charge periods.Battery cells 301 having similar charge periods may refer to batterycells 301 whose charge periods have a difference therebetween that iswithin a predetermined time range. In other words, among the batterycells selected as the battery cell 301 having similar charge periods,the battery cell 301 with the shortest charge period and the batterycell 301 having the longest charge period have a charge perioddifference therebetween that is within a predetermined time range.

The selecting section 312 may judge battery cells 301 having similarcharge periods and similar voltages at each point in time within theircharge periods to be battery cells 301 having similar charge curves. Theselecting section 312 may then select, as the battery cells to beassembled as one battery pack, the battery cells 301 judged to havesimilar charge curves. Battery cells 301 having similar voltages at eachpoint in time within their charge periods may refer to battery cells 301having matching voltages at each point in time. Battery cells 301 havingsimilar voltages at each point in time within their charge periods mayrefer to battery cells 301 having voltages at each point in time thatare within a prescribed voltage range of each other.

The purpose selecting section 313 selects a usage purpose of the batterypack 300, according to the charge curves of the battery cell 301selected as the battery cells 301 to be assemble as the battery pack300. The purpose selecting section 313 may include a table thatassociates charge curves with usage purposes, and may select the usagepurpose based on this table. The usage purpose refers to how the batterypack 300 is to be used, and may include using the battery pack 300 as anemergency power source, a power source for an electric vehicle, or apower source for a personal computer, for example.

FIG. 9 shows exemplary charge curves of three battery cells 301 havingdifferent charge curves. The charge curve 401 represents the chargecurve of a first battery cell 301. The charge curve 402 represents thecharge curve of a second battery cell 301. The charge curve 403represents the charge curve of a third battery cell 301. Based on thesecharge curves, it is seen that the first battery cell 301 has thelongest charge period and the second battery cell 301 has the secondlongest charge period. Furthermore, the third battery cell 301 has theshortest charge period. Since the charge periods of the battery cells301 differ in this way, if these battery cells 301 are assembled as onebattery pack, the battery cells 301 and the overall battery pack 300will quickly deteriorate. In other words, when charging is performedbased on the battery cell 301 with the longest charge period, thebattery cells 301 with shorter charge periods are over-charged, and thiscauses the deterioration to progress. When charging is performed basedon the battery cell 301 with the shortest charge period, the batterycells 301 with longer charge periods end up with lower voltages.

In order to extend the lifetime of the battery cells 301 and the batterypack 300, the selecting section 312 may judge battery cells 301 havingsimilar charge periods as battery cells 301 having similar chargecurves. The selecting section 312 may then select, as the battery cellsto be assembled as a single battery pack, the battery cells 301 havingsimilar charge periods. By assembling the battery pack 300 using thebattery cells 301 that are selected as the battery cells for assemblinga single battery pack, the lifetime of the battery cells 301 and thebattery pack 300 can be extended.

FIG. 10 shows other exemplary charge curves of three battery cells 301having different charge curves. The charge curve 411 represents thecharge curve of a first battery cell 301. The charge curve 412represents the charge curve of a second battery cell 301. The chargecurve 413 represents the charge curve of a third battery cell 301. Basedon these charge curves, it is seen that the first, second, and thirdbattery cells 301 have similar charge periods. However, even though thecharge periods are similar, the voltages of the battery cells at eachpoint in time during their charge periods are different, and thereforeif these battery cells 301 are assembled as one battery pack,deterioration of the battery cells 301 and the overall battery pack 300will progress.

Accordingly, the selecting section 312 may judge battery cells 301having similar charge periods and similar voltages at each point in timewithin their charge periods to be battery cells 301 having similarcharge curves. The selecting section 312 may then select, as the batterycells to be assembled as one battery pack, the battery cells 301 judgedto have similar charge curves. By assembling the battery pack 300 usingthe battery cells 301 selected as the battery cells to be assembled asthe one battery pack, the lifetime of the battery cells 301 and thebattery pack 300 can be extended.

In the above description, battery cells 301 that have been used once arerepacked, but the repacking method described above can be used for newbattery cells 301 that have yet to be used. Even new battery cells 301can have different charge curves. Accordingly, the selecting section 312may select, as the battery cells to be assembled as one battery pack,new battery cells 301 that have similar charge curves from among aplurality of new battery cells 301.

In the above description, the charge curves of the battery cells 301 areacquired, but instead, the selecting section 312 may select, as thebattery cells to be assembled as the one battery pack, battery cellscurrently having similar degrees of deterioration. The current degree ofdeterioration may be the current internal resistance value of thebattery cell 301 or the current voltage of the battery cell 301 whenfully charged. As another example, the battery assembling apparatus 310may acquire the deterioration curves of the battery cells 301. Thebattery assembling apparatus 310 may include a deterioration curveacquiring section that acquires the deterioration curve of each batterycell 301. The deterioration curve acquiring section may acquire thedeterioration curve of each battery cell 301 by acquiring informationindicating the deterioration curve from each memory in a correspondingbattery cell 301. The selecting section 312 may select, as the batterycells 301 to be assembled as one battery pack 300, battery cells 301that have similar deterioration curves and similar current degrees ofdeterioration, from among a plurality of battery cells 301.

Each deterioration curve may indicate the gradual change of the fullycharged voltage of a battery cell 301. In this case, battery cells 301having similar deterioration curves may be battery cells 301 havingfully charged voltage changes that are within a predetermined range. Asanother example, each deterioration curve may indicate change of theinternal resistance value of a battery cell 301. In this case, thebattery cells 301 having similar deterioration curves may be batterycells 301 having internal resistance value changes that are within apredetermined range. The purpose selecting section 313 may select theusage purpose of the battery pack 300 according to the deteriorationcurves of the battery cells 301 selected as the battery cells 301 to beassembled as the battery pack 300. Since these deterioration curvesindicate change in the deterioration of the battery cells 301, thefuture degree of deterioration of the battery cells 301 can be roughlyestimated based on the deterioration curves. Accordingly, the batterycells 301 having similar deterioration curves can be judged as batterycells 301 having similar future degrees of deterioration anddeterioration rates. By assembling the one battery pack 300 usingbattery cells 301 having similar deterioration curves, the lifetime ofthe battery cells 301 and the battery pack 300 can be extended.

The following describes how the battery pack 300 repacking method can beapplied. Each battery cell 301 of the battery pack 300 has a differentdegree of deterioration depending on where the battery cell 301 isarranged in the battery pack 300. For example, if the battery cells 301are sensitive to heat, battery cells 301 arranged near the center of thebattery pack 300 are exposed to more heat than battery cells 301 at theedges of the battery pack 300, and therefore deteriorate more quickly.In other words, battery cells 301 that are surrounded by other batterycells 301 deteriorate more quickly than battery cells 301 that are notsurrounded by other battery cells 301. Accordingly, the deteriorationrate of each battery cell 301 at each arrangement position can beobtained from the deterioration information of each battery cell 301,and the repacking can be performed while arranging the battery cells 301at suitable positions. For example, the battery cell 301 arranged at theposition having the lowest deterioration rate can be repacked at aposition having the highest deterioration rate, and the battery cell 301arranged at the position having the highest deterioration rate can berepacked at a position having the lowest deterioration rate. In thisway, the deterioration rate of each battery cell 301 in the battery pack300 can be made uniform. This repacking may be performed periodically atpredetermined intervals. The deterioration information of each batterycell 301 may be read from the corresponding memory if the battery cell301 includes a memory therein. For a battery cell 301 that does notinclude a memory, the corresponding deterioration information may bemeasured. This process involves an information processing device such asa CPU calculating the deterioration rate at the position where eachbattery cell 301 is arranged, based on the deterioration information ofthe battery cells 301. The information processing device may thencalculate the position at which each battery cell 301 is to be arranged,based on the deterioration information of the battery cells 301 and thedeterioration rate at each arrangement position.

While the embodiments of the present invention have been described, thetechnical scope of the invention is not limited to the above describedembodiments. It is apparent to persons skilled in the art that variousalterations and improvements can be added to the above-describedembodiments. It is also apparent from the scope of the claims that theembodiments added with such alterations or improvements can be includedin the technical scope of the invention.

The operations, procedures, steps, and stages of each process performedby an apparatus, system, program, and method shown in the claims,embodiments, or diagrams can be performed in any order as long as theorder is not indicated by “prior to,” “before,” or the like and as longas the output from a previous process is not used in a later process.Even if the process flow is described using phrases such as “first” or“next” in the claims, embodiments, or diagrams, it does not necessarilymean that the process must be performed in this order.

1. A battery assembling apparatus comprising a selecting section thatselects as battery cells to be assembled into a battery pack, from amonga plurality of battery cells, battery cells having similar charge curvesthat indicate a relationship between voltage and charge period, which isa time period necessary for a battery cell to be charged from a firstvoltage to a second voltage that is higher than the first voltage. 2.The battery assembling apparatus according to claim 1, wherein theselecting section selects as the battery cells to be assembled into thebattery pack, from among the plurality of battery cells, battery cellshaving similar charge periods.
 3. The battery assembling apparatusaccording to claim 1, wherein the selecting section selects as thebattery cells to be assembled into the battery pack, from among theplurality of battery cells, battery cells having similar charge periodsand similar voltages at each of a plurality of times within the chargeperiod.
 4. The battery assembling apparatus according to claim 1,further comprising a charge curve measuring section that charges anddischarges the plurality of battery cells, and measures the charge curveof each battery cell, wherein the selecting section selects, as thebattery cells to be assembled into the battery pack, battery cellshaving similar charge curves as measured by the charge curve measuringsection.
 5. The battery assembling apparatus according to claim 1,further comprising a charge curve reading section that reads informationindicating the charge curves from memories provided respectively in theplurality of battery cells, wherein the selecting section uses theinformation indicating the charge curves read by the charge curvereading section to select, as the battery cells to be assembled into thebattery pack, battery cells having similar charge curves.
 6. The batteryassembling apparatus according to claim 1, further comprising a purposeselecting section that selects a usage purpose for the battery pack,according to the charge curves of the battery cells selected as thebattery cells to be assembled into the battery pack.
 7. A batteryassembling method comprising selecting as battery cells to be assembledinto a battery pack, from among a plurality of battery cells, batterycells having similar charge curves that indicate a relationship betweenvoltage and charge period, which is a time period necessary for abattery cell to be charged from a first voltage to a second voltage thatis higher than the first voltage.